The invention will be better understood with a definition of the types of electrical cable used in both residential and commercial applications. Romex and Lumex are trademarks used to identify particular brands of plastic insulated wire which is also sometimes called non-metallic sheathed cable. Such cables may have 2 or more conductors and the plastic sheathing may be PVC. The formal name is NM cable. Such cable is suitable for use in dry, protected areas (i.e. inside stud walls and on the sides of joists etc.), that are not subject to mechanical damage or excessive heat. Most contemporary homes are wired almost exclusively with NM cables. There are several different categories of NM cable.
NM cable differs from BX cable technically known as armored cable or “AC” that has a flexible aluminum or steel sheath over the conductors and is fairly resistant to damage. Still other cable is surrounded by a rigid metallic conduit. Such cable is required for more hostile environments than the environments in which NM cable is used such as when some moisture is present or the cable is subject to mechanical damage or excessive heat.
Some contractors may extend an NM cable through a wallboard in a manner that only loosely surrounds the cable. Accordingly, the NM cable is more vulnerable to damage than when the same cable is installed within a wall where the cable is protected by wallboard and studs. In addition, the loose engagement of the AC cable with the exterior with a hole that is too large will inherently compromise the integrity of the building fire wall or break. Even installations of junction boxes that extend through the wall board typically have an imperfectly sized and/or shaped hole in the wall board that also compromises the integrity of the building fire wall or break.
Known mounting brackets do not securely mount the AC cable to protect the cable from damage and often do compromise the integrity of the building fire wall or break. Other prior art techniques utilize sleeves and lock nuts to attach the AC cable to junction boxes. Such arrangements are relatively complex and expensive to install. In some cases the mounting of a junction box with conductors that extends through a firewall will compromise the firewall. Thus, it is therefore seen that there exists a need in the art to overcome the deficiencies and limitations described herein and above.